Merge pull request #10713 from thomasballinger/patch-1

Correct suggested git commands for checkout 5.x

README.rst

@@ -74,7 +74,7 b' use IPython from source. You need to checkout the remote 5.x branch. If you are'
 using git the following should work:
 
   $ git fetch origin
-  $ git checkout -b origin/5.x
+  $ git checkout 5.x
 
 If you encounter this error message with a regular install of IPython, then you
 likely need to update your package manager, for example if you are using `pip`